Direct sampler for use in basic oxygen furnaces and the like



March 31, 1970 N. R. CARLSON ET AL 3,503,259

DIRECT SAMPLER FOR USE IN BASIC OXYGEN FURNACES AND THE LIKE Filed June27. 1967 FIG].

5 52 L L 4 so es 64 58 1 62 la INVENTORS 72 Q Norman R. Cor|son,Jumes ECorieton Q and Richard E Putmon A 1 mg at 88) 66 6 74 )ATTORNEY UnitedStates Patent O 3,503,259 DIRECT SAMPLER FOR USE IN BASIC OXYGENFURNACES AND THE LIKE Norman R. Carlson, Export, Richard E. J. Putman,Penn Hills, and James T. Carleton, Pittsburgh, Pa., assignors toWestinghouse Electric Corporation, Pittsburgh, Pa.,

a corporation of Pennsylvania Filed June 27, 1967, Ser. No. 649,235 Int.Cl. G01k 13/12 US. Cl. 73-354 4 Claims ABSTRACT OF THE DISCLOSURE Amolten metal sampling device. A water cooled lancelike member has asampler carrying unit at its lower end and is operated in a basic oxygenfurnace during the decarburizing oxygen blow to withdraw a bath sample.The sampler carrying unit also contains a contact pair operable tosignify the sampling time.

CROSS-REFERENCE TO RELATED APPLICATIONS The following copending patentapplications assigned to the present assignee are related to the presentapplication:

(1) Ser. No. 649.236 entitled Improved System and Method for ControllingCarbon Removal in a Basic Oxygen Furnace, filed by N. R. Carlson, J. T.Carleton and R. E. I. Putman on June 27, 1967.

(2) Ser. No. 649,231 entitled Improved System and Method for ControllingPhosphorus Removal in a Basic Oxygen Furnace, filed by N. R. Carlson onJune 27, 1967.

BACKGROUND OF THE INVENTION The present invention relates to bathsampler devices and more particularly to such devices which have utilityin basic oxygen furnace or similar operating environments.

A direct sampler can form a basis for improved process control inmetalmaking or other furnaces. For example, in basic oxygen steelmakingfurnaces, actual as opposed to estimated levels of carbon and otherelements in a bath can be determined from a sample analysis madepossible by operation of a direct sampler during the decarburizingoxygen blow. As described in the above noted copending applications, thebath can then be steered more accurately and more efliciently by thefurnace control system to the specified carbon and other end-pointlevels.

In other to maximize furnace productivity, it is desirable that bathsampling be effected during continuation of the active bath processing.Thus, as already indicated, it is desirable in the basic oxygen furnacethat the bath sampling be effected during the decarburizing oxygen blowwithout requiring vessel rotation to the turndown position. To providein process bath sampling in a basic oxygen furnace (BOF), the samplermust be able to withstand a flaming atmosphere of 3500 F. and immersionin molten steel and molten slag at 2900 F. for a period of at leastabout /2 minute. Further, the sampler must be withdrawn intact and thesample contained in the sampler must not be oxidized nor melted.

Post endpoint sampling procedures are typical in the prior art andparticularly in the basic oxygen furnace prior art. Thus, after theprocess heat has been turned down or terminated, the vessel is rotatedor opened for insertion of a sampling device typically in the form of anelongated spoon-like element. A sampling procedure of this type impairsfurance production efficiency, yet the spoon-like and similar samplerdevices are not capable of use in th e more efficient in processsampling procedures.

SUMMARY OF THE INVENTION In accordance with the broad principles of thepresent invention, a sampler device comprises an elongated loweringmechanism preferably in the form of a lance-like member having a pinsampler carrying unit at its lower end. The pin sampler unit hasadequate mass and appropriate physical form and physical properties toprotect the pin sampler unit against basic oxygen furnace or similarhigh temperature environments. Preferably, the sampler unit also carriescontact means operable to signify the sampling time and a thermocoupleunit operable to generate a temperature signal.

It is therefore an object of the invention to provide a novel, efficientand economic sampler device operable to obtain bath samples in highlydestructive environments such as those created in basic oxygen furnacesunder decarburizing oxygen blow conditions.

An additional object of the invention is to provide a novel samplerdevice operable to obtain BOF bath samples without requiring BOP vesselturndown and thereby enabling improved BOF production efficiency.

Another object of the invention is to provide a novel sampler devicewhich is operable to obtain a bath sample while producing a signalindicative of the sampling time.

A further object of the invention is to provide a novel sampler devicewhich is operable to obtain a bath sample while producing a signalindicative of the bath temperature.

It is an additional object of the invention to provide a novel samplerdevice which is operable to obtain a bath sample while producing signalsindicative of the sampling time and the bath temperature.

These and other objects of the invention will become more apparent uponconsideration of the following detailed description along with theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 shows a longitudinal sectionof a sampler device constructed in accordance with the principles of theinvention.

FIG. 2 shows a longitudinal section of another lancelike sampler deviceconstructed in accordance with the principles of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS More specifically, there isshown in FIGURE 1 a basic oxygen steelmaking furnace 10 and a samplerdevice 12 therefor including a lance-like and preferably relativelystiff lowering member 14 and a sample carrying unit 16 arranged inaccordance with the principles of the invention. The lance member 14 inthis case is formed from ribbed rod material such as a one-half inchdiameter steel reinforcing rod having laterally projecting ribs 15. Asuitably thick layer 17 of oblative or burnable material is preferablycoated on the rod 14 in order to achieve prolonged useful sampler devicelife.

By oblative material it is means to refer to an inert material or areactive material which tends to burn away in a high temperatureenvironment yet in doing so nonetheless provides thermal protectionbecause heat is carried away with the products of burnup.

The rod 14 extends through a roof of a hood 18 of the BOP 10, and it israised and lowered by operation of suitable drive means (not fullyshown) such as motor driven cogged wheels 20 which, when rotated,interengage with the rod ribs 15 to raise or lower the rod 14.

The length of the rod 14 is adequate to enable the sampler carrying unit16 to be disposed in the furnace bath. For example, the rod 14 may beabout 50 feet long. As indicated in the previously noted copendingapplications, the sampler device 12 can be operatively controlled toobtain a steel sample at a predetermined time point in the steelmakingprocess. Thus, when a sample is to be retrieved, the drive means isactivated to lower the rod 14 from its raised position until the sampledcarrying unit 16 is adequately immersed into the metal bath. Shortlythereafter, the rod 14 is raised until the sampler carrying unit 16 isaccessible from a platform or the like above the hood 18. The entiresampling operation can take place during the decarburizing oxygen blow(i.e., during operating conditions including full oxygen flow rate atlowered oxygen lance position).

The depth at which a sample is obtained in the bath can be relativelyaccurately controlled by controlled operation of the rod drive means.Depth control is particularly advantageous where chemical and.temperature gradients are found to be characteristic of the baths beingsampled thereby making it desirable to obtain samples at substantiallythe same depth or at equivalent depth points from bath to bath ofoperation.

The sampler carrying unit 16 includes a protective barrel member 24which is made or cast from a material such as iron or steel and isprovided with a central opening 26 through which the lower end of therod 14 is extended. Collars 28 and 30 are located above and below thebarrel 214 in conventional set screw or other suitable engagement withthe rod 14 to secure the barrel 24 in place. The collars can have athickness of about /2 inch to assure barrel securance to the rod 14 fora predetermined bath exposure time (such as an amount in excess of thetime required for at least one sampling operation). Generally, thebarrel 24 is provided with adequate size and mass to act as a protectivevehicle for its contained elements under the extreme conditionsencountered within the BOP 10. In a typical case the barrel 24 wouldhave a diameter of 4 inches and a height of 6 inches. Preferably, theexposed barrel and collar surfaces are also coated with a. layer ofoblative material for extended life. A suitable oblative material foruse in coating the barrel and rod surfaces would be a conventionalsprayable refractory material such as that commonly used in the sprayrepair of dolomite and magnesite vessel linings.

The sampler carrying unit 16 also has an additional opening 29 withinwhich a cylinder like enclosure 31 is disposed, and in turn a pinsampler 32 is disposed within the enclosure 31. The pin sampler 32 canbe a commercially available type such as the kind marketed byElectro-Nite Engineering, Philadelphia, Pa. Accordingly, in this casethe pin sampler 32 includes an evacuated glass tube 34 disposed in anopening from the lower side of the enclosure 31 and having an aluminumstrip 36 contained therein. The enclosure 31 is formed from a suitablematerial such as wood to provide a convenient means for assembling anddisassembling the pin sampler 32 in relation to the barrel member 24while protecting the sampler 32 against molten material flow around theoutside thereof.

A disk 38 is secured against the lower end of the enclosure 31 and overthe barrel opening within which the pin sampler 32 is disposed.Securance of the disk 38 is by any suitable means such as by the use ofa high temperature cement. The disk 38 is formed from suitable metalsuch as sheet steel and has a relatively small thickness such as ,5 inchin order to allow time delayed entry of sample material from the steelbath into the sampler tube 34. Thus, as the rod 14 is lowered to movethe sampler carrying unit 16 through the slag, the disk 38 begins tomelt, and it continues to melt as the sampler carrying unit 16 islowered into the molten steel. When the disk 38 is completely melted,molten steel causes the end of the pin sampler tube 34 to melt and steelflows by vacuum into the glass tube 34. Typically, the tube end piece isa low melting point glass to allow quick sample inflow. The sample iskilled by the aluminum strip 36 in the tube, i.e., it is frozen withoutpin holes otherwise resulting from dissolved gaseous oxygen.

The rod 14 is then raised to withdraw the sampler carrying unit 16 fromthe bath, and the enclosure 31 and the pin sampler 32 are removed fromthe barrel member 2-4. The glass tube 34 is broken away from the steelsample which is then made available for analysis. A new enclosure 31 anda new pin sampler 32 and disk 38 are inserted in the barrel member 24for taking the next sample. When the barrel member 24 is substantiallyexpended, it is replaced with a new barrel member and secured to the rod14 by means of new collars 2-8 and 30.

Samplings can be repeated until the structural integrity of the samplerdevice 12 or its rod 14 is no longer' adequate, as determined in part bydesign factors such as materials and dimensions employed. Up to five orsix or more samplings could typically be expected to be made with asampler device of the type shown in FIGURE 1.

In FIG. 2, there is shown a more costly but more durable and moreusefully operating embodiment of the invention. A sampler device 40 inthis instance includes a water cooled lance-like lowering member 42 anda sampler carrying unit 44 having a barrel member 46 similar to thebarrel member 24 of FIG. 1.

The lance member 42 includes an inner tube member 48 having a channelthrough which wires or cabling are extended. An outer tubular jacketmember 50 is disposed about and supported in relation to the inner tube48 by respective partition walls 52 and 54. Respective series connectedsupply and return channels 56 and 58 are thus formed between the members48 and 50 for the flow of coolant such as water. Vertical movement ofthe lance member 42 is controlled by suitable means (not shown) such asa motor driven drum cable or a ratchet type drive. Flexible steel tubingor other piping (not shown) can be used to provide for coolant flow toand from the sampler lance member 42 as it undergoes vertical movement.

At the lower end of the lance member 42, the inner tube 48 is extendedbelow the outer tube 50' for engagement with the barrel member 46 in acentral opening therethrough. An end support wall 60 connects the lowerend of the jacket member 50 to the inner tube member 48 and seals thecoolant channels 56 and 58 from the exterior. Spaces provided betweenthe bottoms of the partition walls 52 and 54 and the end wall60 providefor coolant flow between the supply and return channels 56 and 58.

A side opening is provided through the wall of the inner tube member 48at an environment protected location beneath the top surface of thebarrel member 46 for the passage of the wires in the lance wiringchannel to the barrel member 46. An end portion '62 of the inner tubemember 48 is made solid to provide substantial sealing and protectiveseparation of the wiring channel from the furnace environment.

Collars 64 and 66 are secured as by conventional set screw or othersuitable engagement with the respective lance tube members 50 and 48thereby rigidly ataching the sampler carrying unit 44 to the lancemember 42. The thickness of the collars 64 and 66 is made adequate suchas about /2 inch to assure collar survival over the barrel member life.Further, the barrel member 46, the lance member 42 and the collars 64and 66 preferably have their exposed surfaces covered with an oblativematerial for extended sampler device and sampler carrying unit lives. 7

In the embodiment of FIG. 2, an opening 68 is provided in the barrelmember 46 for an enclosure 70 and a sampler tube 72 in a manner similarto the case of FIG. 1. Opening 74 is also provided for another wood orsimilar enclosure 76. On the bottom side of the enclosure 76, there aresuitably supported within the barrel memher opening 74 a timing signalgenerator such as an inexpensive contact fixture 78 haviug a pair ofnormally open contacts 80 and 82 and preferably also a thermocoupledevice 84, such as a commercially available disposable unit containing aplatinum/platinum-rhodium junction.

Four conductors are suitably extended from the thermocouple device 84and the contact fixture 78 through the enclosure 76 to respectivecontacts which make sliding contact with respective contacts supportedon an inner wall of the barrel member 46. The barrel member inner wallcontacts in turn are connected with four wires which extend to theinmost barrel member opening and as previously described upwardlythrough the. wiring channel in the sampler lance inner tube 48.Preferably the wires and other conductive paths in the thermocouplecircuit are formed from compensated thermocouple lead wires orconductors.

The bottom of the thermocouple and contact opening 74 is enclosed by adisk 86 which is secured to the barrel member 46 as by a hightemperature cement. The disk 86 is preferably substantially identicalwith the disk 88 which is secured across the bottom of the sampler tube72 and the enclosure 70. The thickness of the disks 86 and 88 can, forexample, be about inch.

During the sampling procedure, the substantially identical disks 86 and88 reach a completely melted state at substantially the same time, andbath metal inflow into the opening 74 causes a thermocouple reading tobe generated and further causes a conductive coupling between thecontacts 80 and 82. The connected contacts 80 and 82 complete a circuit(not fully shown) thereby producing a timing signal which veryaccurately defines the process time point to which the sample in thesampler tube 72 and the temperature reading correspond. As indicated inthe previously noted copending applications, such time information isimportant to end point chemistry control in the BOP. For example,without the timing contacts, erroneous identification of the samplingtime point by as small a time span as seconds or less can cause BOF endpoint carbon error by as much as two to three points or more dependingon the rate of oxygen blow and the point in the process at which thesampling is made.

With the provision of a thermocouple reading by the sampler carryingunit 44, there is eliminated the need for a separate cabledthermocoupler bomb device which is conventionally dropped into the BOPbath to generate a temperature reading before it is consumed by the hotenvironment in the furname interior. The thermocouple signal can also beused as a timing signal, and in that event the device 84 provides boththe temperature and the timing signalling functions and the timingsignal generator 78 can be eliminated. However, it is preferred that thetiming signal generator 78 be employed to generate a timing signal aspreviously described primarily because a thermocouple signal wouldgenerally variably lag a contact or other timing signal by as much as 3to 5 seconds. Substantial economy is thus achieved with use of thesampler device of FIG. 2 in that only a thermocouple unit and itsenclosure is expended at about the cost of a bomb each time atemperature reading is obtained. The barrel member 46 is expended aftera number of uses but its cost per use is thus relatively low and furtheris allocable to both the function of obtaining a bath sample and thefunction of obtaining a temperature reading.

The sampler device 40 is operated in a manner similar to that describedfor the sampler device 12 of FIGURE 1. However, the enclosure 76 and thethermocouple unit 84 and the timing contact unit 78 as well as theenclosure 70and the sampler tube 72 are replaced after each sampling.The barrel member 46 is replaced only as required (such as after everyfour to six uses or more). The sampler lance 42 is characterized with arelatively long operating life as a result of the positive coolingsupplied for it.

Both described embodiments of the invention enable improved furnaceproductivity to be achieved. In the BOP application in particular,sampling can be obtained without vessel turndown and withoutinterruption of the steelmaking oxygen blow process.

The foregoing description has been presented only to illustrate theprinciples of the invention. Accordingly, it is desired that theinvention not be limited by the embodiments described, but, rather, thatit be accorded an interpretation consistent with the scope and spirit ofits board principles.

What is claimed is:

1. A sampler carrying member comprising a body member having adequateproperties and mass and size to withstand basic oxygen furnaceconditions as severe as decarburizing oxygen blow conditions for atleast a predetermined exposure time sufficient to allow for bath sampleretrieval, said body member having an opening therein, a sampler unitoperable to accept a bath sample when a part of its external surfacearea is exposed to bath material, means for supporting and enclosingsaid sampler unit in said body member opening so as normally to protectthe external surfaces of said sampler unit from exposure to the bathmaterial, said sampler unit supporting and enclosing means including ameltable member secured in relation to said body member between saidsampler unit surface part and the exterior, said body member havinganother opening therein, a timing signal unit operable to effectgeneration of a timing signal indicative of the point in time at whichsaid timing signal unit is exposed to bath material, means forsupporting and enclosing said timing signal unit in a part of said bodymember other opening so as normally to protect said timing signal unitfrom exposure to the bath material, said timing signal unit supportingand enclosing means including another meltable member secured inrelation to said body member between said other opening part and theexterior, conductor means extending from said timing signal unit throughsaid body member for transmitting the timing signal, both of saidmeltable members having adequate properties and mass and size to enabletheir survival for body member entry into the bath and to enable bathmaterial inflow to said units after bath entry prior to consumption ofsaid body member to an irretrievable state.

2. A sampler carrying member as set forth in claim 1 wherein said bodymember is a barrel-like member, said barrel member has an axial openingfor receiving a supporting member, the first mentioned openings arelocated along respective axes substantially parallel to the axial barrelopening axis, said supporting and enclosing means includes respectiveremovable thermally insulative members disposed in the firstmentionedopenings from one side thereof, said meltable members securedin relation to said barrel member across the other side of the firstmentioned openings respectively.

3. A sampler device for use in a basic oxygen furnace or the like, saidsampler device comprising a sampler carrying member having adequateproperties and mass and size to withstand internal furnace conditions assevere as decarburizing oxygen blow conditions for at least apredetermined exposure time sufficient to allow for bath sampleretrieval, an opening in said sampler carrying member, a sample unitoperable to accept a bath sample when a part of its external surfacearea is exposed to bath material, means for supporting and enclosingsaid sampler unit in said sampler carrying member opening so as toprotect the external surfaces of said sampler unit from exposure to thebath material during carrying member entry into the bath and so as toenable bath material inflow to said sampler unit after bath entry, saidsampler carrying unit having another opening, a timing signal unitoperable to effect generation of a timing signal representative of thepoint in time at which said timing signal unit is exposed to the bathmaterial, means for supporting and enclosing said timing signal unit ina part of said carrying member other opening so as to protect saidtiming signal unit from exposure to the bath material during carryingmember entry into the bath and so as to enable bath material inflow tosaid timing signal unit at substantially the same time as bath materialinflows to said sampler unit, a thermocouple unit for generating asignal representing bath temperature when exposed to bath material,means for supporting and enclosing said thermocouple unit in saidcarrying member other opening part so as to protect said thermocoupleunit from exposure to the bath material during carrying member entryinto the bath and so as to enable bath material inflow to saidthermocouple unit, an elongated lance-like member having an end portionmovable between the furnace interior bath region and a region remotetherefrom, means for establishing and maintaining coolant flow withinsaid lance member during sampler device operation, means for securingsaid sampler carrying member to said elongated member end portion,conductor means extending from said timing signal unit through saidsampler carrying member for transmitting the timing signal, conductormeans extending from said thermocouple unit through said samplercarrying member for transmitting the thermocouple signal, and meansforming an interior and longitudinal cooled channel within said lancemember for passage of wiring to said conductor means.

4. A sampler device for use in a basic oxygen furnace or the like, saidsampler device comprising a sampler carrying member having adequateproperties and mass and size to withstand internal furnace conditions assevere as decarburizing oxygen blow conditions for at least apredetermined exposure time sufficient to allow for bath sampleretrieval, an opening in said sampler carrying member, a sampler unitoperable to accept a bath sample when a part of its external surfacearea is exposed to bath material, means for supporting and enclosingsaid sampler unit in said sampler carrying member opening so as toprotect the external surfaces of said sampler unit from exposure to thebath material during carrying member entry into the bath and so as toenable bath material inflow to said sampler unit after bath entry, saidsampler carrying member having another opening, a timing contact unitfor generating a timing signal, means for supporting and enclosing saidtiming unit in a part of said carrying member other opening so as toprotect said unit from exposure to the bath material during carryingmember entry into the bath and so as to enable bath material inflow tosaid unit after bath entry, conductor means extending from said unitthrough said sampler carrying member for transmitting the timing signal,an elongated lance-like member having an end portion movable between thefurnace interior bath region and a region remote therefrom, means forthermally protecting said lance member against internal furnaceconditions as severe as decarburizing oxygen blow conditions to anextent suflicient to allow repeated use of said lance member inobtaining bath samples, said protecting means including means forestablishing and maintaining coolant flow within said lance memberduring sampler operations, means forming an interior and longitudinalcooled channel within said lance member for passage of wiring to saidtiming signal conductor means, means for securing said sampler carryingmember to said lance member end portion, and means for driving saidlance member into and out of the furnace interior so as to control theposition of said sampler carrying member.

References Cited UNITED STATES PATENTS 3,313,159 4/1967 Vanderbeck73-423 2,463,427 3/1949 Richards 73--359 3,038,951 6/1962 Mead 1362343,250,125 5/1966 Bonn 73-343 3,288,654 11/1966 Perrin et al 73343 X3,357,250 12/ 1967 Lowdermilk 73-354 FOREIGN PATENTS 1,025,026 4/ 1966Great Britain.

S. CLEMENT SWISHER, Primary Examiner US. Cl. X.R.

